Systemic lupus erythrematosus (SLE) is a deadly autoimmune disease with a broad range of clinical manifestations. A leading cause of morbidity and mortality in patients with SLE is cardiovascular disease (CVD). Due to the multifactorial nature of SLE it can be envisaged that a broad panel of biomarkers will be needed to pro- vide biomolecular signatures of the array of clinical manifestations, including increased risk of CVD. We have discovered 1-chlorofatty aldehyde (1-ClFALD) as a novel myeloperoxidase (MPO)-generated lipid oxidation product that is increased 1,400-fold in the vascular wall of human atheromas. Recently we showed that 1-chlo- rofatty acid (1-ClFA) and 1-chlorofatty alcohol (1-ClFOH) are stable metabolites of 1-ClFALD that are present in human serum. Preliminary data suggest that serum levels of the 1-chlorofatty acids, 2-chlorohexadecanoic acid and 2-chlorooctadecanoic acid, are elevated in subjects with SLE compared to a control group of subjects with a similar incidence of CVD. Thus, it is likely that biomarkers of in vivo vascular wall MPO activity may prove to be powerful predictors of active SLE and increased cardiovascular risk in SLE patients. The overall goal of this proposal is to examine the relationship between serum levels of both 1-ClFA, as well as 1- ClFOH, with cardiovascular outcomes in an established longitudinal SLE cohort where the primary data has been collected measuring surrogate imaging markers of CVD. Dr. Rosalind Ramsey-Goldman of Northwestern University will provide us with these human serum samples from the SOLVABLE study. SOLVABLE is a 5-year longitudinal epidemiological study where imaging surrogate markers of CVD have been measured. There are two specific aims for this proposal. Specific Aim 1 will test the hypothesis that serum levels of 1-ClFA and 1-ClFOH are elevated in SLE subjects with CVD. Subclinical CVD has been defined in the SOLVABLE study by surrogate imaging measures of disease (i.e., IMT, PI, CAC and AC). Comparisons of these chlorinated lipids as predictors of CVD will be made between SLE and control subjects. Further comparisons will be made between chlorinated lipids and other potential biomarkers including C-reactive protein, cholesterol, LDL, HDL, and oxidized LDL that have previously been quantified in the SOLVABLE study, as well as MPO, which will be quantified in this study. Specific Aim 2 will test the hypothesis that baseline 1-ClFA and 1-ClFOH levels predict 36 month change in imaging markers of subclinical CVD in SLE subjects. Change will be defined as the difference in measures of surrogate imaging markers between year 3 and baseline. Comparisons of these chlorinated lipids as predictors of CVD progression will be made between SLE and control subjects and will be compared to the available data on other pro-inflammatory biomarkers already measured in these subjects. The availability of the collected samples at Northwestern University coupled with cardiovascular imaging data provides an extraordinary opportunity to identify these chlorinated lipid species as novel bio- markers of CVD in this well-defined group of SLE patients. PUBLIC HEALTH RELEVANCE: Systemic lupus erythrematosus (SLE) is a deadly autoimmune disease with a broad range of clinical manifestations. A leading cause of morbidity and mortality in patients with SLE is cardiovascular disease. The overall goal of this proposal is to examine the relationship between serum levels of chlorinated lipids with previously collected data from SLE subjects where the primary data collection has focused on measuring surrogate imaging markers of cardiovascular disease.